The present invention relates to a connection end-fitting for a flexible fluid transport line, the flexible line comprising a pressure sheath, an interlocked pressure vault arranged outwardly relative to the pressure sheath and at least one traction armor layer arranged outwardly relative to the interlocked pressure vault, the armor layer comprising a plurality of armor elements, the end-fitting comprising:                an end region of the interlocked pressure vault,        at least one end segment of each armor element,        an end vault and a cover fastened on the end vault, the end vault and the cover defining a chamber between them for receiving each end segment of the armor elements,        a front crimping flange of the pressure sheath attached on the end vault and arranged outwardly relative to the end region of the interlocked pressure vault,        a system for locking the interlocked pressure vault relative to the end vault.        
The flexible line is advantageously a flexible pipe of the unbonded type designed to transfer hydrocarbons through a body of water, such as an ocean, sea, lake or river. Alternatively, the flexible line is an umbilical reinforced by armor elements or a cable.
Such a flexible pipe is for example made according to normative documents API 17J (Specification for Unbonded Flexible Pipe) and API RP 17B (Recommended Practice for Flexible Pipe) established by the American Petroleum Institute.
The pipe is generally formed by a set of concentric and superimposed layers. It is considered “unbonded” within the meaning of the present invention when at least one of the layers of the pipe is able to move longitudinally relative to the adjacent layers when the pipe is bent. In particular, an unbonded pipe is a pipe with no bonding materials connecting the layers forming the pipe.
The pipe is generally positioned through a body of water, between a bottom assembly, designed to collect the fluid mined in the bottom of the body of water, and a floating or stationary surface assembly designed to connect and distribute the fluid. The surface assembly may be a semisubmersible platform, an FPSO or another floating assembly.
Some of these pipes are used under very harsh conditions. Thus, the transport of hydrocarbons may have a very high pressure and temperature, for example a pressure comprised between 500 bars and 1500 bars, and a temperature comprised between 110° C. and 130° C. Furthermore, in the case where the pipe is submerged at a great depth, said pipe must be capable of withstanding a very high outside pressure, for example approximately 250 bars if the pipe is submerged at a depth of 2500 meters.
The pipes intended for great depths must also withstand very high tensions, commonly several tens of tons, to which they are subjected during use and/or during their installation at sea.
Furthermore, in the case where the surface assembly is floating and movable based on the sea conditions, the risers connecting the seabed to the surface assembly may sometimes be subject to millions of curve variation cycles. These risers must therefore also be cable of lastingly withstanding dynamic fatigue stresses.
The connection end-fittings, which are especially stressed, must also be designed to withstand such usage conditions.
However, the existing flexible pipe end-fittings sometimes have weak areas at the connection of the pressure vault of the flexible pipe to the tip. Such weak areas can cause an axial displacement, or even a separation of the pressure vault relative to the tip.